#define _CRT_SECURE_NO_WARNINGS 
#include <stdio.h>
int main() {
    int a, b, c, d;
    scanf("%d%d%d%d", &a, &b, &c, &d);
    int x = a;
    if (x < b)
        x = b;
    if (x < c)
        x = c;
    if (x < d)
        x = d;
    printf("%d", x);
    return 0;
}